镁合金高温熔体定量输送浇注装置

采用输送装置，防止镁合金高温熔体在成形输送和浇注过程中出现氧化、燃烧，并对输送和浇注进行定量，是镁合金大量生产很重要的工艺手段。本文对镁合金高温熔体定量输送浇注装置的结构及工艺特点进行了综合和分析，并展望了其发展趋势。     

高温镁合金熔体定量输送的研究

通过设计一套叶片式轴流泵镁液输送系统,根据流量输送试验,得到了定量输送的数学模型,由此开发出基于PLC控制的定量输送系统。镁液输送实际应用表明：本输送系统定量输送误差在±5％以内。     

镁合金熔液的定量输送技术

镁液的定量输送技术是镁合金成形中的关键技术,概述了目前国内外在这方面的研究进展.分别介绍了电磁泵定量供液系统、柱塞泵定量、减压式自动浇注、气压泵定量等方法的工作原理及其特点,提出了选择定量加料方式时应注意的事项.     

铸造镁合金熔炼技术进展

综述了近年来国外镁合金熔炼气体保护技术,熔炼炉设计和镁液浇注技术及装置的最新研究成果。     

镁合金熔体输送装置的设计及应用

针对镁合金高温熔体易氧化、燃烧的特点,研究开发了容积定量、气压输送,并具有液流止回机构的镁合金高温熔体输送装置。经工厂应用,特别是试生产圆盘状压铸件,结果表明,输送量的平均值标准误差为0.014、方差均值为0.061,输送定量精度达到±5%,能有效地防止镁合金熔体回流、吸气及氧化。     

镁合金压铸技术进展

镁合金工程结构件的成型方法以压铸为主,热室或冷室压铸是镁合金成型的主要方法.为克服传统压铸技术在镁合金压铸中的缺陷,人们研究开发了一些新的压铸技术.     

镁合金压铸过程中的阻燃研究及其进展

综述了国内外在压铸过程中所采用的阻燃方法。在这些阻燃方法中 ,添加合金元素法对镁合金阻燃具有明显作用 ,富Ce稀土的添加同样对镁合金的阻燃具有显著作用。试验结果表明富Ce稀土的添加可使镁合金起燃温度提高 70℃。认为中国镁合金防燃的重点应放在普通冷室压铸机条件下通过添加稀土加以解决     

气压输送自动定量浇注装置中PLC的应用

本文介绍气压输送自动定量浇注装置的研制和采用FX2－80MR型可编程控制器完成自动定量浇注装置的控制,着重讨论了定量器组合提高浇注精度和利用可编程控制器的中断技术作及时故障处理的方法。     

镁合金压铸技术的研究现状

介绍了镁合金压铸件的特性及应用,压铸技术的发展及应用等研究现状;讨论了镁合金压铸技术面临的挑战与机遇,指出了镁合金压铸技术的发展方向。     

镁合金压铸技术和装备的现状与展望

在简述镁合金熔铸物化学特性及高品质压铸件生产工艺要求的基础上,介绍了当今压铸镁合金熔化浇注、压铸工艺装备、压铸产品开发、压铸工艺废料重熔精炼技术与装备现状,指出了依托技术与装备进步、采用现代产品及工艺模具优化设计技术,是镁合金压铸生产企业快速、高效、低风险形成生产能力、参与市场竞争的关键。     

镁合金铸造成型最新研究进展

近年来镁合金在汽车轻量化方面发挥了积极的作用。为了适应镁合金快速发展的需求,镁合金的铸造技术,尤其是压铸技术得到了长足的发展。在传统铸造工艺的基础上介绍了几种镁合金铸造工艺的新进展,主要包括镁合金真空低压消失模铸造新技术、镁合金液态压铸锻造双控成型技术、充氧压铸技术、真空压铸技术、半固态压铸技术、镁合金双辊连续铸轧技术及镁合金电磁连续铸造技术。     

铸造AZ91D镁合金的遗传性

试验研究了具有不同铸造组织形态的AZ91D镁合金和具有不同晶粒度的AZ91D镁合金重熔前后的组织和性能的变化规律。结果表明,重熔前后的AZ91D镁合金的组织和性能具有相同性或相似性,在铸造过程中具有明显的遗传性。     

Establishment of hydrogen measurement system for magnesium alloy melt

The equations of hydrogen solubility in pure magnesium and its alloy were deduced based on thermodynamic analysis： for pure magnesium, lgc（H）=0.51g p（H2）-1 332/T＋0.568; for AZ91 alloy, lgc（H）=0.51g p（H2）-1 332/T＋0.483. Based on the above equations, a rapid and reliable measurement system for hydrogen content in magnesium melt was set up with CPU controller and electric circuit..With this instrument, measurement experiments were carried out to determine hydrogen content in AZ91 melt. The results show that the actual hydrogen level of AZ91 melt under gas protection varies from 0.06 mL/g to 0.14 mL/g at the temperature range from 650 ℃ to 750 ℃ and hydrogen content lineally increases with the increase of temperature.     

基于Pro/E镁合金壳体压铸模设计

分析镁合金壳体的结构特点,介绍压铸模浇注系统设计,使用Pro/E软件完成铸件三维实体造型和优化的压铸模结构设计。经实际生产检验:模具在使用中操作方便、安全,工作稳定可靠,铸件质量达到要求。     

国内外镁合金成形技术专利分析

介绍国内外镁合金研发动态,选择镁合金成形技术的德温特专利,对镁合金成形技术专利在不同国家、不同时间、不同工艺、不同申请单位等方面的情况进行了分析。指出我国对于镁合金成形技术的研究还没有足够的自主知识产权。     

Numerical simulation of standing waves for ultrasonic purification of magnesium alloy melt

It was attempted to enhance and accelerate the separation of oxidation inclusions from magnesium alloy melt by virtue of ultrasonic agglomeration technology. In order to investigate the feasibility and effectiveness of standing waves for ultrasonic purification of magnesium alloy melt, numerical simulation and relevant experiment were carried out. The numerical simulation was broken into two main aspects. On one hand, the ultrasonic field propagations within the cells with various shapes were characterized by numerical solutions of the wave equation and with a careful choice of geometry a nearly idealized standing wave field was finally obtained. On the other hand, within such a standing wave field the agglomeration behavior of oxidation inclusions in magnesium alloy melt was analyzed and discussed. The agglomeration time and agglomeration position of oxidation inclusions were predicted with numerical simulation method. The results show that the oxidation inclusions whose apparent densities are close to the density of the melt can agglomerate at wave nodes in a short time which to a great extent enhances and accelerates the separation of oxidation inclusions from magnesium alloy melt.     

镁合金薄壳压铸件充型凝固与热应力数值分析

以镁合金航空仪表壳为例,建立三维模型和有限差分模型,通过数值模拟镁合金薄壳在高压铸造过程中的充型温度场、凝固过程温度场及凝固过程应力场。分析模拟结果发现:在压铸过程中铸件局部温降梯度大的部分容易引起凝固过程的不一致,导致铸件局部应力过大,加大铸件的热裂倾向,通过分析结果预测铸件裂纹发生的区域,预测结果与实际情况吻合,并对原工艺提出相应的改进措施。     

Protection behavior of fluorine-containing cover gases on molten magnesium alloys

The sulphur hexa-fluoride gas（SF6）, which is commonly used as the cover gas of molten magnesium alloys in the magnesium industry today, has an extremely high global warming potential（GWP）. The protection mechanism of SF6 containing cover gases on molten magnesium alloys was presented. The cover gas protects the melt by reacting with the melt to form a coherent protective film on the melt surface. The film contains MgO and MgF2. Particles containing MgF2 form on the interface between the oxide film and the bulk magnesium alloy, which correspond to the concave areas from the surface observation. These particles increase the Pilling and Bedworth ratio of surface film and enhance the protective capability of the films. Based on the understanding of the mechanism of SF6, a melting technology in a sealed furnace was proposed, and the protection behavior of magnesium alloys in the sealed melting furnace was investigated under the protective atmosphere containing HFC-134a. The morphology and composition of the surface film were also studied. Experiments to evaluate the protective effect of two other fluorine containing gases with low GWPs on AZglD alloy in the sealed furnace were also carried out, and the results show that the new gases are potential substitutes for SF6.     

基于数值模拟的镁合金手机壳体压铸模浇注系统的设计与优化

设计良好的浇口及浇注系统对获得高质量的压铸件十分重要。针对金属型模具的不透明性,采用数值模拟技术对镁合金手机壳体浇口及浇注系统进行优化,设计出两种类型的浇口及浇注系统进行数值分析。初步设计中采用等截面扇形横浇道浇注系统,导致中部不充分流动,过早地关闭了型腔的边界,使最后填充的区域留在铸件不易设溢流槽和排气槽的中部,导致铸件中形成气体夹杂,此法不适合。采用等厚度扇形横浇道浇注系统,数值模拟表明：新设计提供了均匀的熔体填充模型,使最后填充区域位于易放置溢流槽和排气槽的大按键的边界上,从而使压铸模具的设计得到优化。